In the management and treatment of a wound (defined herein to mean any injury or opening in tissue) there are three primary objectives: (1) prevention of infection, (2) preservation and/or restoration of function, and (3) preservation and/or restoration of cosmetic appearance. The most important of these objectives is the prevention of infection. Success in the prevention of infection directly affects the healing process and the degree to which the other two objectives, function and cosmetic appearance, can be preserved and/or restored.
In the case of wounds, the presence of bacteria is the single cause of infection. It is known that the number of bacteria, rather than bacterial type, is a critical determinant of whether a wound becomes infected. Experimental evidence suggests that a critical level of bacteria is approximately 105 organisms per gram of tissue. Below this level, wounds heal; at levels greater than 105 bacteria per gram of tissue, wounds often become infected. All traumatic wounds are contaminated by the time the wound is presented to a medical care facility for treatment (Dire, Daniel I. [1990] “A comparison of Wound Irrigation Solutions Used in the Emergency Department,” Annals of Emergency Medicine 19(6):704-708). Dirty wounds, or those which have not been treated within six hours, are likely to be contaminated with bacteria at levels which are higher than the critical level. Reducing the number of bacteria in and around the wound is a recognized and accepted means for avoiding infection and expediting wound healing.
Different procedures of wound management have been developed to help decrease the level of bacteria present in a wound, i.e., reduce the incidence of infection. The cleansing of a wound and the site surrounding the wound to remove blood clots, debris, dirt, or other foreign materials which can introduce contaminants, including pathogenic microorganisms, is critical in reducing levels of bacteria in and around the wound. There are numerous wound cleansing procedures presently used by healthcare professionals such as debridement, excision and irrigation. See, for example, Sinkinson, Craig Alan, ed. (1989) “Maximizing A Wound's Potential For Healing,” Emergency Medicine Reports 10(11):83-89; Lammers, Richard L. (1991) “Soft Tissue Procedures: Principles of Wound Management,” in Clinical Procedures in Emergency Medicine, Roberts and Hedges, eds., 2nd Ed., W. B. Saunders Company, pp. 515-521; Cracroft, Davis (1987) “Minor Lacerations and Abrasions,” Emergency Medicine: A Comprehensive Review, Kravis and Warner, eds., 2nd cd., Aspen Publishing Co., pp. 107-110; and Mulliken, John B. (1984) “Management of Wounds,” in Emergency Medicine, May ed., John Wiley & Sons, pp. 283-286.
Irrigation is the most commonly used procedure for cleansing of open contaminated wounds.
Irrigation involves the application of sterile solutions or fluids to wounds to remove loose devitalized tissue, bacterial inoculum, blood clots, loose debris, and foreign bodies proximate to and within the depths of the wound. The two critical components of any effective wound irrigation method and/or device are: (1) the application of an adequate volume of sterile irrigation solution to the wound, and (2) the use of sufficient pressure applied in an effective dispersal pattern in the delivery of the solution to effectively remove contaminants. Regarding volume, the amount of irrigation solution required will depend upon the type of wound and the level of contamination. Injuries which can introduce a high amount of bacteria into a wound (such as puncture wounds and bites) may require 1 liter or more of irrigation solution. See Mulliken, 1989. Regarding pressure, it has been demonstrated that stream pressure of a minimum of 4 pounds per square inch (psi) (and, preferably, 7 psi) is required to effectively flush or remove contaminants from a wound. See, for example, Rodeheaver G T. Wound Cleaning, Wound Irrigation, Wound Disinfection, In: Krasner D., Kane D. Chronic Wound Care. 2nd ed. Wayne, P. A.:Health Management Publications; 1997, pp 97-108; and Bergstrom N., Bennett, M. A., Carlson, C. E. et al. Treatment of Pressure Ulcers. Clinical Guideline No. 15. AHCPR Publication No. 95-0652. Rockville, Md. Department of Health and Human Services. Public Health Services, Agency of Health Care Policy and Research; December 1994. Irrigation pressure in excess of desired limits (e.g., 25 psi or greater) may actually drive bacteria and particulate matter deeper into the wound and thereby defeat the purpose of the irrigation process. High-pressure irrigation may also cause damage to healthy tissue and impede the tissue's defenses and retard healing. Thus, effective wound irrigation requires the use and application of adequate volumes of irrigation solution delivered to the wound in an effective dispersal pattern at appropriate pressures.
Bulb syringes or gravity flow irrigation devices deliver fluid at low pressures and as such are ineffective in ridding wounds of small particulate matter or in sufficiently reducing wound bacterial counts. Irrigation by bulb syringe exerts a pressure of about 0.05 psi, which does not reduce the number of bacteria or particulate contaminants enough to prevent infection. The flow rate of irrigation fluid delivered through intravenous (IV) tubing can be enhanced by inflation of a blood pressure cuff around a collapsible plastic IV bag. This method is cumbersome and provides considerably less irrigation pressure than can be delivered by a plunger-type syringe.
The plunger-type syringe is the most common irrigation device currently used. Its use involves filling the barrel of the syringe with sterile irrigation solution and depressing the plunger to generate and apply a single pressurized stream of solution in and around the wound to dislodge and rinse away contaminants. This device has two notable disadvantages: (1) an extremely limited reservoir of irrigation fluid (typically a syringe with a 35 cc-capacity barrel), and (2) it is limited to dispersal and application of a single concentrated stream of solution to the wound. Consequently, in most cases, the syringe must be repeatedly refilled in order to apply sufficient quantities of irrigation solution to a wound. This is time-consuming and cumbersome to do while attempting to maintain a sterile field. In an attempt to address this limitation, a device has been developed that involves a system consisting of a syringe and IV tubing with a valve system that attaches to a bottle of saline to provide a ready means of refilling the syringe barrel. (Travenol pressure irrigation set, code no. 2D2113, or irriget, Ackrad Laboratories, Garwood, N.J.). Additionally, U.S. Pat. No. 4,357,937 describes a disposable, manually operable medical irrigation device which is adapted for providing selective volume and stream intensity in liquid flow from a plurality of syringes. These devices do not adequately address the disadvantages of using syringes for irrigation as discussed above and are not commonly used in clinical practice due to their complexity of use and cost.
The amount of hydraulic pressure that can be delivered with a plunger-type syringe varies with the force exerted on the plunger of the syringe and with the internal diameter of the attached needle. Plunger-type syringe devices that deliver moderate pressure employ either a 19 gauge needle attached to a 35 cc syringe, which creates hydraulic pressure in the range of 7-8 psi, or a 30 ml syringe fitted with a 19 gauge needle which typically creates about 7 psi irrigation pressure. A 22 gauge needle attached to a 12 cc syringe, delivers a pressure of about 13 psi. Such pressures have been proven effective in wound irrigation, but, as stated above, such devices apply only a single stream of solution to the wound. In addition, these described devices hold less than adequate volumes of irrigation solution and therefore require repeated refilling which is time consuming and cumbersome.
U.S. Pat. No. 5,071,104 describes a wound irrigation apparatus and process for cleansing wounds which includes a pressure bladder, e.g., a blood pressure cuff, disposed proximate a reservoir holding a cleaning solution. The device in the '104 patent also includes a flexible tubular conduit for transmitting the solution from the reservoir to a single nozzle. The conduit and reservoir form a two-part system which is time consuming to set up, inconvenient to use, and costly.
U.S. Pat. No. 5,133,701 describes a disposable pressurized wound irrigation device which has a pressurized chamber for providing a force upon the reservoir such that a single liquid stream of cleansing solution is expelled from the device at a constant pressure. A propellant is used in evacuating the cleanser contents of the device. This invention requires a propellant and involves a relatively elaborate manufacturing and filling process which is labor intensive and requires specialized machinery. This device is also inconvenient to use and costly.
The subject invention successfully addresses the above described disadvantages associated with the previously known devices and methods, and provides certain attributes and advantages which have not been realized by these known devices.